JERUSALEM - Israeli archaeologists said Monday they may have found the earliest evidence yet for the existence of modern man.

The discovery is far from conclusive. If confirmed, however, it could upset theories of the origin of humans.

A Tel Aviv University team excavating the Qesem cave in central Israel said teeth found in the cave were about 400,000 years old and resemble those of other remains of modern man, known as Homo sapiens, found in Israel.

The earliest other Homo sapiens remains are half as old.

"It's very exciting to come to this conclusion," said archaeologist Avi Gopher, whose team examined the teeth with X-rays and CT scans and dated them according to the layers of earth where they were found.

He stressed that further research was needed to solidify the claim. If it does, he says, "this changes the whole picture of evolution."

The accepted scientific theory is that Homo sapiens originated in Africa and migrated out. Gopher said that if the remains are definitively linked to modern humans' ancestors, it could mean that they originated in the Middle East. The report was published in the American Journal of Physical Anthropology.

Sir Paul Mellars, a prehistory expert at Cambridge University, said the study was reputable, and the find is "important" because remains from that critical time period are scarce. But it is premature, he said, to call them human.

"Based on the evidence they've cited, it's a very tenuous and frankly rather remote possibility," Mellars said. Teeth are often unreliable indicators of origin, he said, and the remains are more likely related to modern man's ancient relatives, the Neanderthals.

Current scientific theory holds that modern humans and Neanderthals stemmed from a common ancestor who lived in Africa about 700,000 years ago. One group of descendants migrated to Europe and developed into Neanderthals, later becoming extinct. Another group stayed in Africa and evolved into Homo sapiens - modern humans.